Ensure the engineLayer is disposed when an OpacityLayer is disabled (#94280)
diff --git a/packages/flutter/lib/src/rendering/layer.dart b/packages/flutter/lib/src/rendering/layer.dart
index 711303d..7c617b4 100644
--- a/packages/flutter/lib/src/rendering/layer.dart
+++ b/packages/flutter/lib/src/rendering/layer.dart
@@ -1764,11 +1764,16 @@
@override
void addToScene(ui.SceneBuilder builder) {
assert(alpha != null);
- bool enabled = firstChild != null; // don't add this layer if there's no child
+
+ // Don't add this layer if there's no child.
+ bool enabled = firstChild != null;
if (!enabled) {
+ // Ensure the engineLayer is disposed.
+ engineLayer = null;
// TODO(dnfield): Remove this if/when we can fix https://github.com/flutter/flutter/issues/90004
return;
}
+
assert(() {
enabled = enabled && !debugDisableOpacityLayers;
return true;
diff --git a/packages/flutter/test/rendering/layers_test.dart b/packages/flutter/test/rendering/layers_test.dart
index 8d4e2dc..1d9aa4a 100644
--- a/packages/flutter/test/rendering/layers_test.dart
+++ b/packages/flutter/test/rendering/layers_test.dart
@@ -637,6 +637,21 @@
expect(builder.addedPicture, true);
expect(layer.engineLayer, isA<FakeOpacityEngineLayer>());
});
+
+ test('OpacityLayer dispose its engineLayer if there are no children', () {
+ final OpacityLayer layer = OpacityLayer(alpha: 128);
+ final FakeSceneBuilder builder = FakeSceneBuilder();
+ layer.addToScene(builder);
+ expect(layer.engineLayer, null);
+
+ layer.append(PictureLayer(Rect.largest)..picture = FakePicture());
+ layer.addToScene(builder);
+ expect(layer.engineLayer, isA<FakeOpacityEngineLayer>());
+
+ layer.removeAllChildren();
+ layer.addToScene(builder);
+ expect(layer.engineLayer, null);
+ });
}
class FakeEngineLayer extends Fake implements EngineLayer {
